How to make asset look more "3d" (sail of a sailboat)
You can use one of these 2 solutions:
The Sculpt solution:

Create your sail, curve it a bit:



In Sculpt mode, select the Mask brush (don't use a Subdivision Surface modifier for the moment if you want the mask to be visible), paint the 3 corners:




Select the Cloth Filter brush, keep the Type &gt; Gravity, paint until you get this kind of result:



The Cloth solution:

Create your sail, select vertices on the 3 corners and make it a vertex group, give the object a Cloth physics with the group as Pin Group, give it a constraint &gt; Copy Scale, here on the X axis and with the edge as Target:



Create an edge under the sail, create a Force Field &gt; Wind with a Strength of, for example, 3000:



Play the animation, the wind will blow on the surface, scale down the edge so that it folds a bit the sail, scroll in the Timeline, when you're good, apply the Cloth modifier: